Answer a) roof equilibrium temperature is 400K
Explanation:
The roof surface is sorrounded by ambient air whose temperature is 300K and which has a convective coefficient h of 10W/m2-K.
This means that heat will be conducted to the roof from the air around at an heat Flux of 300K x 10W/m2-K = 3000w/m2
For a clear solar day with solar heat Flux of 500W/m2, total heat Flux on roof will be
Q = 500 + 3500 = 3500W/m2
Q = h(Tr-Ta)
Ts is temperature of roof,
Ta is temperature of air
3500 = 10(Tr - 50)
350 = Tr - 50
Tr = 400k
Answer b): roof equilibrium temperature will be 350K
Explanation:
At night total heat Flux is only due to hot ambient air sorrounding the surface of the roof.
Q = 3000W/m2
Q = h(Tr-Ta)
3000 = 10(Tr-50)
300 = Tr - 50
Tr = 350K
Answer: the surface shear stress at x =1m from the leading edge of the plate is 4.1973 N/m²
Explanation:
Given that;
density s = 1.16 kg/m³
velocity = u = 50 m/s
kinetic viscosity r = 15.89 × 10⁻⁶ m²/s
xL = 1m from the leading edge of the plate
Now Reynold number (Rex)
Rex = UxL / r
Rex = (50 m/s × 1m ) / 15.89 × 10⁻⁶ m²/s
Rex = 3146633.1025
since Rex is greater than 5×10⁵ { Turbulent flow }
so Local skin friction coefficient
⇒ Cfx = 0.0577 / (Rex)^1/5
Cfx = 0.0577 / (3146633.1025)^1/5
Cfx = 0.0028947
Now Shear stress (y)
y = Cfx × 1/2 × su²
y = 0.0028947 × 1/2 × 1.16 × (50)²
y = 4.1973 N/m²
∴ the surface shear stress at x =1m from the leading edge of the plate is 4.1973 N/m²
Answer:
Kinetic energy is what makes the object move. Many rides use the transfer of potential energy to kinetic energy to move along the track. When the roller coaster moves downwards, kinetic energy is generated. The maximum kinetic energy generated is when the roller coaster is at the bottom of the track.
Explanation: